Software copyright protection is a central concern in software development, and in copyright law itself. Typically, software is distributed in shrink-wrap packages containing diskettes and/or CD-ROMs, and over the Internet via ftp servers. Protecting, software from rampant unauthorized copying, distribution and use ("software piracy") is one of the most challenging problems facing the software industry.
Over the past years, several techniques have been developed 1or combating software piracy. These include use of hardware plugs, use of license keys, use of tokens and sophisticated encryption systems.
One of the leading technologies for controlling use of software within turnkey transaction systems is the Digital Rights Management system of InterTrust.RTM. Technologies Corp. of Sunnyvale, Calif., as described in U.S. Pat. Nos. 5,892,900, 5,410,598, 5,050,213, 4,977,594 and 4,827,508. Information about InterTrust is available on the web at http://www.intertrust.com.
Another such leading technology is the CyberSales Solution.TM. of SoftLock.com, Inc. of Maynard, Mass., as described in U.S. Pat. No. 5,509,070. CyberSales Solution provides locking and unlocking functionality so that content can be securely previewed by consumers, electronically purchased and redistributed, and it protects the content in an initial transaction and in subsequent information pass-along. Content providers can control how much information is available without paying, and disable, or additionally charge for, the ability to print or cut and paste. CyberSales Solution handles secure transactions, remittance processing, reports, audits and customer service. Information about CyberSales Solution is available on the web at http://www.softlock.com.
With the advent of the use of compelling multi-media on web pages accessible over the Internet, protection of digital images and other media is becoming increasingly critical. Web designers are reluctant to use valuable digital "works of art" knowing that users can easily copy them onto their own computers, and use them for their own unauthorized purposes. Moreover, anyone using a web browser to view an image posted on the Internet can easily copy the image by simply positioning a mouse pointer over the displayed image, clicking on the right mouse button and selecting a "Save Image As . . ." command. Copyright and piracy issues are major problems for web publishers.
Prior art techniques for protecting digital images include the embedding of invisible digital watermarks within images, so that copies of protected images can be traced. Digimarc Corporation of Lake Oswego, OR embeds hidden messages within pixel data for identifying protected images, and tracks their distribution over the Internet to monitor potential copyright infringement. Digimarc images carry unique IDs that link to predetermined locations on the web. Digimarc images are compatible with standard image formats, such as JPEG, and can be opened and displayed by standard image readers. However, when opened with a Digimarc reader, the images are displayed together with a "Web look up" button that enables a user to identify the sources of the images. Digimarc technology is described in U.S. Pat. Nos. 5,862,260, 5,850,481, 5,841,978, 5,841,886, 5,832,119, 5,822,436, 5,809,160, 5,768,426, 5,765,152, 5,748,783, 5,748,763, 5,745,604, 5,721,788, 5,710,834 and 5,636,292. Information about Digimarc is available on the web at http://www.digimarc.com.
These techniques are useful in thwarting digital image piracy to the extent that they trace pirated content, but they do not prevent unauthorized copying of digital images in the first place.
Other prior art techniques require a webmaster to modify images residing on a server computer in order to protect them. The webmaster is also required to modify his web pages accordingly, so as to reference the modified images. SafeMedia.TM. is a software product of Internet Expression, Inc. of Exton, Pa. that converts images from a standard format such as JPEG into SIF (Safe Image Format). SIF images can only be viewed with a SafeMedia Java viewer. SafeMedia embeds a host or domain name into an image, and checks that the image is located on the web site it was intended for. SafeMedia also includes enhanced system control for preventing screen capture by disabling a clipboard. Information about SafeMedia is available on the web at http://www.safemedia.com.
These techniques are difficult to embrace, since they require modification of all protected images on the web, as well as modification of the web pages that reference them. Furthermore the SIF Java viewer has the limitation of only being able to load images from the same server that the viewer came from.
Other prior art techniques for protecting digital images use Java applets within web browsers to disable the menu that pops up when a user right clicks on a displayed image within his web browser. Copysight.RTM. is a software application of Intellectual Protocols, LLC of Nanuet, N.Y. that uses digital watermarking and fingerprinting to protect images, and includes a Java applet that disables the ability to save displayed images within a web browser and the ability to print them. Copysight operates by converting unprotected files to protected files that are encrypted and that contain digital fingerprints. Copysight also tracks distribution of protected images across the Internet, and issues reports of potential copyright infringement. It allows a web administrator to select which files are to be protected. Information about Copysight is available on the web at http://www.ip2.com.
These techniques disable unauthorized copying of digital images from within web browsers, but they do not protect the images from being copyed by an application external to the web browser. For example, they do not prevent a user from copying digital images displayed in his web browser by means of an application running external to the web browser, such as an image editing tool, or by means of a Print Screen or other such command that serves to copy contents of a video buffer to a clipboard. Thus a Java applet that prevents unauthorized copying of digital images from within Netscape Communicator or Internet Explorer can be circumvented by a user pressing on a Print Screen button of his keyboard, or by a user copying and pasting from a window of his web browser to a window of another software application.